Now we deal with normal size pages and huge pages we need
to tell the place handlers the size we're dealing with
and make sure the temporary page is large enough.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20170224182844.32452-8-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Record the largest page size in use; we'll need it soon for allocating
temporary buffers.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20170224182844.32452-7-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Unfortunately madvise DONTNEED doesn't work on hugepagetlb
so use fallocate(FALLOC_FL_PUNCH_HOLE)
qemu_fd_getpagesize only sets the page based off a file
if the file is from hugetlbfs.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20170224182844.32452-6-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Create ram_block_discard_range in exec.c to replace
postcopy_ram_discard_range and most of ram_discard_range.
Those two routines are a bit of a weird combination, and
ram_discard_range is about to get more complex for hugepages.
It's OS dependent code (so shouldn't be in migration/ram.c) but
it needs quite a bit of the innards of RAMBlock so doesn't belong in
the os*.c.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20170224182844.32452-5-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
At the start of the postcopy phase, partially sent huge pages
must be discarded. The code for dealing with host page sizes larger
than the target page size can be reused for this case.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20170224182844.32452-4-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
When using postcopy with hugepages, we require the source
and destination page sizes for any RAMBlock to match; note
that different RAMBlocks in the same VM can have different
page sizes.
Transmit them as part of the RAM information header and
fail if there's a difference.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20170224182844.32452-3-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Replace the host page-size in the 'advise' command by a pagesize
summary bitmap; if the VM is just using normal RAM then
this will be exactly the same as before, however if they're using
huge pages they'll be different, and thus:
a) Migration from/to old qemu's that don't understand huge pages
will fail early.
b) Migrations with different size RAMBlocks will also fail early.
This catches it very early; earlier than the detailed per-block
check in the next patch.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20170224182844.32452-2-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
hmp_savevm calls qemu_savevm_state(f), which sets to_dst_file=f in
global migration state. Then hmp_savevm closes f (g_free called).
Next access to to_dst_file in migration state (for example,
qmp_migrate_set_speed) will use it after it was freed.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170225193155.447462-5-vsementsov@virtuozzo.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Version bumps break backwards migration; update the docs
to explain to people that's bad and how to avoid it.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20170210110359.8210-1-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This leak was introduced in commit
581f08bac2.
(it stands out quickly with ASAN once the rest of the leaks are also
removed from make check with this series)
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Juan Quintela <quintela@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20170221141451.28305-31-marcandre.lureau@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Commit a3a3d8c7 introduced a segfault bug while checking for
'dc->vmsd->unmigratable' which caused QEMU to crash when trying to add
devices which do no set their 'dc->vmsd' yet while initialization.
Place a 'dc->vmsd' check prior to it so that we do not segfault for
such devices.
NOTE: This doesn't compromise the functioning of --only-migratable
option as all the unmigratable devices do set their 'dc->vmsd'.
Introduce a new function check_migratable() and move the
only_migratable check inside it, also use stubs to avoid user-mode qemu
build failures.
Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
Message-Id: <1487009088-23891-1-git-send-email-ashijeetacharya@gmail.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
To fix migration between 2.7 and 2.8, some fields have
been renamed and managed with the help of a PHB property
(pre_2_8_migration):
5c4537b spapr: Fix 2.7<->2.8 migration of PCI host bridge
So we need to add them to the white list:
dma_liobn[0],
mem_win_addr, mem_win_size,
io_win_addr, io_win_size
become
mig_liobn,
mig_mem_win_addr, mig_mem_win_size,
mig_io_win_addr, mig_io_win_size
CC: David Gibson <david@gibson.dropbear.id.au>
CC: Dr. David Alan Gilbert <dgilbert@redhat.com>
CC: Thomas Huth <thuth@redhat.com>
CC: Greg Kurz <groug@kaod.org>
CC: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20170214133331.28997-1-lvivier@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Let's have a test for ptr arrays to some primitive type with some
not-null and null ptrs intermixed.
Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170222160119.52771-6-pasic@linux.vnet.ibm.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Add test for VMSTATE_ARRAY_OF_POINTER_TO_STRUCT with an array
containing some null pointer.
Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170222160119.52771-5-pasic@linux.vnet.ibm.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Fixed type case in assert to uintptr_t rather than uint64_t
Make VMS_ARRAY_OF_POINTER cope with null pointers. Previously the
reward for trying to migrate an array with some null pointers in it was
an illegal memory access, that is a swift and painless death of the
process. Let's make vmstate cope with this scenario.
The general approach is, when we encounter a null pointer (element),
instead of following the pointer to save/load the data behind it, we
save/load a placeholder. This way we can detect if we expected a null
pointer at the load side but not null data was saved instead.
Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Guenther Hutzl <hutzl@linux.vnet.ibm.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170222160119.52771-4-pasic@linux.vnet.ibm.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Currently vmstate_base_addr does several things: it pinpoints the field
within the struct, possibly allocates memory and possibly does the first
pointer dereference. Obviously allocation is needed only for load.
Let us split up the functionality in vmstate_base_addr and move the
address manipulations (that is everything but the allocation logic) to
load and save so it becomes more obvious what is actually going on. Like
this all the address calculations (and the handling of the flags
controlling these) is in one place and the sequence is more obvious.
The newly introduced function vmstate_handle_alloc also fixes the
allocation for the unused VMS_VBUFFER|VMS_MULTIPLY|VMS_ALLOC scenario
and is substantially simpler than the original vmstate_base_addr.
In load and save some asserts are added so it's easier to debug
situations where we would end up with a null pointer dereference.
Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170222160119.52771-3-pasic@linux.vnet.ibm.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
The vmstate_(load|save)_state start out with an a void *opaque pointing
to some struct, and manipulate one or more elements of one field within
that struct.
First the field within the struct is pinpointed as opaque + offset, then
if this is a pointer the pointer is dereferenced to obtain a pointer to
the first element of the vmstate field. Pointers to further elements if
any are calculated as first_element + i * element_size (where i is the
zero based index of the element in question).
Currently base_addr and addr is used as a variable name for the pointer
to the first element and the pointer to the current element being
processed. This is suboptimal because base_addr is somewhat
counter-intuitive (because obtained as base + offset) and both base_addr
and addr not very descriptive (that we have a pointer should be clear
from the fact that it is declared as a pointer).
Let make things easier to understand by renaming base_addr to first_elem
and addr to curr_elem. This has the additional benefit of harmonizing
with other names within the scope (n_elems, vmstate_n_elems).
Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170222160119.52771-2-pasic@linux.vnet.ibm.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Using QMP, the error message of 'migrate_set_downtime' was displaying
the values in milliseconds, being misleading with the command that
accepts the value in seconds:
{ "execute": "migrate_set_downtime", "arguments": {"value": 3000}}
{"error": {"class": "GenericError", "desc": "Parameter 'downtime_limit'
expects an integer in the range of 0 to 2000000 milliseconds"}}
This message is also seen in HMP when trying to set the same
parameter:
(qemu) migrate_set_parameter downtime-limit 3000000
Parameter 'downtime_limit' expects an integer in the range of 0 to
2000000 milliseconds
To allow for a proper error message when using QMP, a validation
of the user input was added in 'qmp_migrate_set_downtime'.
Signed-off-by: Daniel Henrique Barboza <danielhb@linux.vnet.ibm.com>
Message-Id: <20170222151729.5812-1-danielhb@linux.vnet.ibm.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
We want to use the ccw bios to start final network boot. To do
this we use ccw bios to detect if the boot device is a virtio
network device and retrieve the start address of the
network boot image.
Signed-off-by: Farhan Ali <alifm@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Load the network boot image into guest RAM when the boot
device selected is a network device. Use some of the reserved
space in IplBlockCcw to store the start address of the netboot
image.
A user could also use 'chreipl'(diag 308/5) to change the boot device.
So every time we update the IPLB, we need to verify if the selected
boot device is a network device so we can appropriately load the
network boot image.
Signed-off-by: Farhan Ali <alifm@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Add new field to S390IPLState to store the name of the network boot
loader.
Signed-off-by: Farhan Ali <alifm@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
The current QEMU ROM infrastructure rejects late loading of ROMs.
And ELFs are currently loaded as ROM, this prevents delayed loading
of ELFs. So when loading ELF, allow the user to specify if ELF should
be loaded as ROM or not.
If an ELF is not loaded as ROM, then they are not restored on a
guest reboot/reset and so its upto the user to handle the reloading.
Signed-off-by: Farhan Ali <alifm@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Now that the all callbacks have been converted to use "at" syscalls, we
can drop this code.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_open2() callback is vulnerable to symlink attacks because it
calls:
(1) open() which follows symbolic links for all path elements but the
rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
mkdir(), both functions following symbolic links for all path
elements but the rightmost one
(4) local_post_create_passthrough() which calls in turn lchown() and
chmod(), both functions also following symbolic links
This patch converts local_open2() to rely on opendir_nofollow() and
mkdirat() to fix (1), as well as local_set_xattrat(),
local_set_mapped_file_attrat() and local_set_cred_passthrough() to
fix (2), (3) and (4) respectively. Since local_open2() already opens
a descriptor to the target file, local_set_cred_passthrough() is
modified to reuse it instead of opening a new one.
The mapped and mapped-file security modes are supposed to be identical,
except for the place where credentials and file modes are stored. While
here, we also make that explicit by sharing the call to openat().
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_mkdir() callback is vulnerable to symlink attacks because it
calls:
(1) mkdir() which follows symbolic links for all path elements but the
rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
mkdir(), both functions following symbolic links for all path
elements but the rightmost one
(4) local_post_create_passthrough() which calls in turn lchown() and
chmod(), both functions also following symbolic links
This patch converts local_mkdir() to rely on opendir_nofollow() and
mkdirat() to fix (1), as well as local_set_xattrat(),
local_set_mapped_file_attrat() and local_set_cred_passthrough() to
fix (2), (3) and (4) respectively.
The mapped and mapped-file security modes are supposed to be identical,
except for the place where credentials and file modes are stored. While
here, we also make that explicit by sharing the call to mkdirat().
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_mknod() callback is vulnerable to symlink attacks because it
calls:
(1) mknod() which follows symbolic links for all path elements but the
rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
mkdir(), both functions following symbolic links for all path
elements but the rightmost one
(4) local_post_create_passthrough() which calls in turn lchown() and
chmod(), both functions also following symbolic links
This patch converts local_mknod() to rely on opendir_nofollow() and
mknodat() to fix (1), as well as local_set_xattrat() and
local_set_mapped_file_attrat() to fix (2) and (3) respectively.
A new local_set_cred_passthrough() helper based on fchownat() and
fchmodat_nofollow() is introduced as a replacement to
local_post_create_passthrough() to fix (4).
The mapped and mapped-file security modes are supposed to be identical,
except for the place where credentials and file modes are stored. While
here, we also make that explicit by sharing the call to mknodat().
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_symlink() callback is vulnerable to symlink attacks because it
calls:
(1) symlink() which follows symbolic links for all path elements but the
rightmost one
(2) open(O_NOFOLLOW) which follows symbolic links for all path elements but
the rightmost one
(3) local_set_xattr()->setxattr() which follows symbolic links for all
path elements
(4) local_set_mapped_file_attr() which calls in turn local_fopen() and
mkdir(), both functions following symbolic links for all path
elements but the rightmost one
This patch converts local_symlink() to rely on opendir_nofollow() and
symlinkat() to fix (1), openat(O_NOFOLLOW) to fix (2), as well as
local_set_xattrat() and local_set_mapped_file_attrat() to fix (3) and
(4) respectively.
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_chown() callback is vulnerable to symlink attacks because it
calls:
(1) lchown() which follows symbolic links for all path elements but the
rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
mkdir(), both functions following symbolic links for all path
elements but the rightmost one
This patch converts local_chown() to rely on open_nofollow() and
fchownat() to fix (1), as well as local_set_xattrat() and
local_set_mapped_file_attrat() to fix (2) and (3) respectively.
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_chmod() callback is vulnerable to symlink attacks because it
calls:
(1) chmod() which follows symbolic links for all path elements
(2) local_set_xattr()->setxattr() which follows symbolic links for all
path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
mkdir(), both functions following symbolic links for all path
elements but the rightmost one
We would need fchmodat() to implement AT_SYMLINK_NOFOLLOW to fix (1). This
isn't the case on linux unfortunately: the kernel doesn't even have a flags
argument to the syscall :-\ It is impossible to fix it in userspace in
a race-free manner. This patch hence converts local_chmod() to rely on
open_nofollow() and fchmod(). This fixes the vulnerability but introduces
a limitation: the target file must readable and/or writable for the call
to openat() to succeed.
It introduces a local_set_xattrat() replacement to local_set_xattr()
based on fsetxattrat() to fix (2), and a local_set_mapped_file_attrat()
replacement to local_set_mapped_file_attr() based on local_fopenat()
and mkdirat() to fix (3). No effort is made to factor out code because
both local_set_xattr() and local_set_mapped_file_attr() will be dropped
when all users have been converted to use the "at" versions.
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_link() callback is vulnerable to symlink attacks because it calls:
(1) link() which follows symbolic links for all path elements but the
rightmost one
(2) local_create_mapped_attr_dir()->mkdir() which follows symbolic links
for all path elements but the rightmost one
This patch converts local_link() to rely on opendir_nofollow() and linkat()
to fix (1), mkdirat() to fix (2).
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
When using the mapped-file security model, we also have to create a link
for the metadata file if it exists. In case of failure, we should rollback.
That's what this patch does.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_rename() callback is vulnerable to symlink attacks because it
uses rename() which follows symbolic links in all path elements but the
rightmost one.
This patch simply transforms local_rename() into a wrapper around
local_renameat() which is symlink-attack safe.
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_renameat() callback is currently a wrapper around local_rename()
which is vulnerable to symlink attacks.
This patch rewrites local_renameat() to have its own implementation, based
on local_opendir_nofollow() and renameat().
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_lstat() callback is vulnerable to symlink attacks because it
calls:
(1) lstat() which follows symbolic links in all path elements but the
rightmost one
(2) getxattr() which follows symbolic links in all path elements
(3) local_mapped_file_attr()->local_fopen()->openat(O_NOFOLLOW) which
follows symbolic links in all path elements but the rightmost
one
This patch converts local_lstat() to rely on opendir_nofollow() and
fstatat(AT_SYMLINK_NOFOLLOW) to fix (1), fgetxattrat_nofollow() to
fix (2).
A new local_fopenat() helper is introduced as a replacement to
local_fopen() to fix (3). No effort is made to factor out code
because local_fopen() will be dropped when all users have been
converted to call local_fopenat().
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_readlink() callback is vulnerable to symlink attacks because it
calls:
(1) open(O_NOFOLLOW) which follows symbolic links for all path elements but
the rightmost one
(2) readlink() which follows symbolic links for all path elements but the
rightmost one
This patch converts local_readlink() to rely on open_nofollow() to fix (1)
and opendir_nofollow(), readlinkat() to fix (2).
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_truncate() callback is vulnerable to symlink attacks because
it calls truncate() which follows symbolic links in all path elements.
This patch converts local_truncate() to rely on open_nofollow() and
ftruncate() instead.
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_statfs() callback is vulnerable to symlink attacks because it
calls statfs() which follows symbolic links in all path elements.
This patch converts local_statfs() to rely on open_nofollow() and fstatfs()
instead.
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_utimensat() callback is vulnerable to symlink attacks because it
calls qemu_utimens()->utimensat(AT_SYMLINK_NOFOLLOW) which follows symbolic
links in all path elements but the rightmost one or qemu_utimens()->utimes()
which follows symbolic links for all path elements.
This patch converts local_utimensat() to rely on opendir_nofollow() and
utimensat(AT_SYMLINK_NOFOLLOW) directly instead of using qemu_utimens().
It is hence assumed that the OS supports utimensat(), i.e. has glibc 2.6
or higher and linux 2.6.22 or higher, which seems reasonable nowadays.
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_remove() callback is vulnerable to symlink attacks because it
calls:
(1) lstat() which follows symbolic links in all path elements but the
rightmost one
(2) remove() which follows symbolic links in all path elements but the
rightmost one
This patch converts local_remove() to rely on opendir_nofollow(),
fstatat(AT_SYMLINK_NOFOLLOW) to fix (1) and unlinkat() to fix (2).
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_unlinkat() callback is vulnerable to symlink attacks because it
calls remove() which follows symbolic links in all path elements but the
rightmost one.
This patch converts local_unlinkat() to rely on opendir_nofollow() and
unlinkat() instead.
Most of the code is moved to a separate local_unlinkat_common() helper
which will be reused in a subsequent patch to fix the same issue in
local_remove().
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_lremovexattr() callback is vulnerable to symlink attacks because
it calls lremovexattr() which follows symbolic links in all path elements
but the rightmost one.
This patch introduces a helper to emulate the non-existing fremovexattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lremovexattr().
local_lremovexattr() is converted to use this helper and opendir_nofollow().
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_lsetxattr() callback is vulnerable to symlink attacks because
it calls lsetxattr() which follows symbolic links in all path elements but
the rightmost one.
This patch introduces a helper to emulate the non-existing fsetxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lsetxattr().
local_lsetxattr() is converted to use this helper and opendir_nofollow().
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_llistxattr() callback is vulnerable to symlink attacks because
it calls llistxattr() which follows symbolic links in all path elements but
the rightmost one.
This patch introduces a helper to emulate the non-existing flistxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to llistxattr().
local_llistxattr() is converted to use this helper and opendir_nofollow().
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_lgetxattr() callback is vulnerable to symlink attacks because
it calls lgetxattr() which follows symbolic links in all path elements but
the rightmost one.
This patch introduces a helper to emulate the non-existing fgetxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lgetxattr().
local_lgetxattr() is converted to use this helper and opendir_nofollow().
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The local_open() and local_opendir() callbacks are vulnerable to symlink
attacks because they call:
(1) open(O_NOFOLLOW) which follows symbolic links in all path elements but
the rightmost one
(2) opendir() which follows symbolic links in all path elements
This patch converts both callbacks to use new helpers based on
openat_nofollow() to only open files and directories if they are
below the virtfs shared folder
This partly fixes CVE-2016-9602.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
This patch opens the shared folder and caches the file descriptor, so that
it can be used to do symlink-safe path walk.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
When using the passthrough security mode, symbolic links created by the
guest are actual symbolic links on the host file system.
Since the resolution of symbolic links during path walk is supposed to
occur on the client side. The server should hence never receive any path
pointing to an actual symbolic link. This isn't guaranteed by the protocol
though, and malicious code in the guest can trick the server to issue
various syscalls on paths whose one or more elements are symbolic links.
In the case of the "local" backend using the "passthrough" or "none"
security modes, the guest can directly create symbolic links to arbitrary
locations on the host (as per spec). The "mapped-xattr" and "mapped-file"
security modes are also affected to a lesser extent as they require some
help from an external entity to create actual symbolic links on the host,
i.e. another guest using "passthrough" mode for example.
The current code hence relies on O_NOFOLLOW and "l*()" variants of system
calls. Unfortunately, this only applies to the rightmost path component.
A guest could maliciously replace any component in a trusted path with a
symbolic link. This could allow any guest to escape a virtfs shared folder.
This patch introduces a variant of the openat() syscall that successively
opens each path element with O_NOFOLLOW. When passing a file descriptor
pointing to a trusted directory, one is guaranteed to be returned a
file descriptor pointing to a path which is beneath the trusted directory.
This will be used by subsequent patches to implement symlink-safe path walk
for any access to the backend.
Symbolic links aren't the only threats actually: a malicious guest could
change a path element to point to other types of file with undesirable
effects:
- a named pipe or any other thing that would cause openat() to block
- a terminal device which would become QEMU's controlling terminal
These issues can be addressed with O_NONBLOCK and O_NOCTTY.
Two helpers are introduced: one to open intermediate path elements and one
to open the rightmost path element.
Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
(renamed openat_nofollow() to relative_openat_nofollow(),
assert path is relative and doesn't contain '//',
fixed side-effect in assert, Greg Kurz)
Signed-off-by: Greg Kurz <groug@kaod.org>
If these functions fail, they should not change *fs. Let's use local
variables to fix this.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
